Pomelo Peel Extract as Corrosion Inhibitor for Steel in Simulated Seawater and Acidic Mediums

Abstract

This study was aimed to establish the possibility of using an eco-friendly plant-based pomelo peel with different concentrations to formulate a novel corrosion green inhibitor for steel applications in 3.5% NaCl and 0.1 M HCl solutions at 30 °C. The corrosion rate and inhibition efficiency were evaluated using weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques corresponded with surface morphology characterization of the corroded steel samples without and with inhibitors using a scanning electron microscope (SEM) and energy-dispersive x-ray analysis (EDS). Based on the Fourier-transform infrared spectroscopy (FTIR) results, it was found that the pomelo peels extract is a mixture of the chemical compounds of naringin (C27H32O14), auraptene (C19H22O3) and naringenin-4′-O-glucoside (C21H22O10). The results were also indicated that there is a remarkable improvement in the inhibition efficiency and corrosion rate of low-carbon steel after the addition of inhibitor, and as well as the immersion time was profound to have a significant effect on the corrosion behavior of the different concentrations of inhibitor. The pomelo peels extract of 8000 ppm concentration gave the best inhibition efficiency of 74.64 and 71.15% in 0.1 M HCl and 3.5% NaCl, respectively. The adsorption isotherm of pomelo peels within different concentrations on the steel surface conforms Langmuir’s isotherm, and the thermodynamic parameters of Kads and ΔG have also been calculated and discussed.